M←NCCH3, M-η2-(NC)-CH3, and CN-M-CH3 Prepared by Reactions of Ce, Sm, Eu, and Lu Atoms with Acetonitrile: Matrix Infrared Spectra and Theoretical Calculations

Fei Cong; Juanjuan Cheng; Han-Gook Cho; Tengfei Huang; Xuefeng Wang; Lester Andrews

doi:10.1021/acs.inorgchem.1c02232

M←NCCH₃, M-η²-(NC)-CH₃, and CN-M-CH₃ Prepared by Reactions of Ce, Sm, Eu, and Lu Atoms with Acetonitrile: Matrix Infrared Spectra and Theoretical Calculations

Inorg Chem. 2021 Dec 6;60(23):17649-17656. doi: 10.1021/acs.inorgchem.1c02232. Epub 2021 Nov 8.

Authors

Fei Cong¹, Juanjuan Cheng¹, Han-Gook Cho², Tengfei Huang¹, Xuefeng Wang¹, Lester Andrews³

Affiliations

¹ School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
² Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012 South Korea.
³ Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia 22904-4319, United States.

PMID: 34747602
DOI: 10.1021/acs.inorgchem.1c02232

Abstract

The reactions of laser-ablated Ce, Sm, Eu, and Lu atoms with acetonitrile were studied by matrix infrared spectra in a neon matrix, and M←NCCH₃, M-η²-(NC)-CH₃, and CN-M-CH₃ were identified with isotopic substitution and quantum chemical calculations. The major product is the insertion complex (CN-M-CH₃), while the end-on and side-on complexes (M←NCCH₃ and M-η²-(NC)-CH₃) are also trapped in the matrix. The CCN antisymmetric stretching mode for Ce-η²-(NC)-CH₃ was observed at 1536.9 cm^-1, which is much lower than the same modes observed for other lanthanides. NBO analysis reveals that Ce exhibits a remarkable 4f-orbital contribution in bonding to N and to C, reconfirming an active 4f-orbital contribution of cerium in bonding in the side-on complex, while the 4f contributions of Sm and Eu to the M-N and M-C bonds are much lower and the 4f orbital of Lu is not involved in bonding.